The present invention relates to a wafer baking automatic machine. More particularly, it relates to a wafer baking automatic machine which has a housing including housing side walls and a housing cover defining a baking chamber, an endless rotatable chain of baking clamps movable in the baking chamber and having baking plates and guiding rollers guided on guiding rails, heating burners arranged to heat the baking plates, and an air supply conduit in a lower region of the baking chamber and at least one air discharge conduit in the housing cover.
Wafers and similar baking goods are baked in an automated working cycle in wafer baking automatic machines. After filling of dough between the baking plates the closed baking clamps pass through the baking chamber and are heated by the heating burner. In order to retain the required energy consumption as low as possible, it is known in such a wafer baking automatic machine to arrange in a discharge stack a heat exchanger for a heat recovery so that a fresh air supplied to the heating burner is pre-heated in the heat exchanger. Such construction is disclosed in the German Patent No. 2,448,902.
High preheating of the supplied air is, however, to be retained within certain limits since this air as a so-called flushing air must be cooled through the bearing of the guiding rollers of the baking clamps and the hinges of the baking clamp. The heating action of the heating burner is affected so that the hot discharge gas produced by the heating burners is mixed with the flushing air which has a substantially lower temperature. To the contrary, the temperature of the flushing air increases during mixing with the discharge gases of the heating burner first of all in the upper region of the baking chamber so that here the temperature load of the bearing points and material is especially high and reaches the permissible limit.
The walls surrounding the insulation of the baking chamber must satisfy high requirements since the temperature acting in the baking chamber and determined by the baking process must be insulated from the surroundings. The thus produced high temperature difference requires not only high expenses for the insulation, but also leads to considerable heat loss.